[gardencreek]

I have a 5 gallon all grain batch of pale, OG: 1058, used treated RO water, mashed at 150 deg, negative iodine reaction, pitched 1600 ml starter of wyeast 1056 and fermented at 68 deg. 1 week in primary, 14 days in secondary. After primary, everything was purged and pushed with CO2. I bottled out of a corny with a beer gun. Bottle conditioned with 1 cup of priming sugar and everything was sanitized with idophor (mixed 2 tsp to 3 gal H2O).

Left the bottles in the lager box at 68deg for 3 weeks. If the beer is room temp I can get a little bit of CO2 out of solution with agitation, none if they are cold. Gravity is 1006.

It makes no sense to me. I took some of the same caps and recapped a known carbonated beer, got it hot, shook it up and put it under water, no gas leakage. I'm starting to think the priming sugar might have been mislabeled lactose but I'm not getting the mouth feel or taste I would expect with an addition of lactose.

What have I missed?

[dmtaylor]

It sounds like you might indeed have used lactose.  A full cup of corn sugar in 5 gallons would have been overprimed and gushing after 3 weeks and you are seeing the opposite.  I think this is the most likely explanation.

Why the full cup, anyway?  Standard priming would be 3/4 cup in 5 gallons.

[gardencreek]

A full cup weighs about 5 ounces and by my feeble calculations, it should produce 2.8 to 3 volumes CO2. I can force carb but there is something about bottle conditioned beer that I like better. 

I'm tinkering with carbonation levels where, even if the initial pour has to be very cold, the effervescence at ale temp is high, thereby giving me the full sensory profile. Is it to style guidelines? Nope not even close. I enjoy the subtle mingling's of the malt, hops and yeast aromas as much as the actual flavors. If it makes me slobber like my dog then it's a winner.

[Jimmy K]

It sounds like you might indeed have used lactose.  A full cup of corn sugar in 5 gallons would have been overprimed and gushing after 3 weeks and you are seeing the opposite.  I think this is the most likely explanation.

Why the full cup, anyway?  Standard priming would be 3/4 cup in 5 gallons.

5oz is standard, but for the dextrose I buy, 3/4 cup is only ~3oz. It is very light and fluffy. I haven't measured by volume since I figured that out.

[dmtaylor]

FWIW, I don't use corn sugar at all anymore, ever.  About 5/8 cup regular cane or beet sugar in 5 gallons is perfect.  And it doesn't fluff, so it's pretty darned consistent.

[gardencreek]

FWIW, I don't use corn sugar at all anymore, ever.  About 5/8 cup regular cane or beet sugar in 5 gallons is perfect.  And it doesn't fluff, so it's pretty darned consistent.

Out of curiosity, have you noticed any significant difference in the head or lacing with the cane or beet sugar?

Thanks.

[dmtaylor]

Heck no.  If you want a lot of head, add more than the standard amount of sugar.  If you want a creamier head, use wheat or rye or a ton of hops.  Same as anyone would do even if they used corn sugar.  The differences between the different sugars in qualities of the head or carbonation or flavor or anything else are ZERO.  Use what's cheap and easily available.  For me, in my kitchen, I've always got a couple pounds of beet sugar in the cabinet.  Snatch a little of that and you're golden.  Just keep in mind that whatever amount you used for corn sugar, you only need 80% as much of beet or cane sugar, as it's a little "stronger".

[Jimmy K]

Just keep in mind that whatever amount you used for corn sugar, you only need 80% as much of beet or cane sugar, as it's a little "stronger".

Is that 80% by volume or weight? Or both?

[hubie]

If you have a scale, you'll want to use do it by weight for consistency.  Corn sugar can be fluffy.  Table sugar can be very consistent if you use the same brand, so if you can get by measuring by volume if you find a certain amount that works well for you.  However, if you switch brands from time to time, you can get different grain sizes that will pack differently so your volume measurement can change.

I wholeheartedly agree about using table sugar.  It is cheap and easy to get.  I target a certain CO2 level I want, then weigh out the amount of table sugar I need.  I'll use a bag of corn sugar if I have it, such as if it came in a kit, but I'll still weigh out how much I'd want to use.  To do the calculation, for simplicity I use Palmer's nomograph, but there are plenty of online calculators for that.

As for the differences in amount to use, table vs. corn, the math is that for every gram of sucrose you use, you generate 0.51 grams of CO2; for every gram of pure corn sugar you use, you generate 0.49 grams CO2.  Most likely if you get your corn sugar from the homebrew shop, it will be glucose monohydrate, which has water bound to it to keep it from clumping.  In that case, for every gram of that you use, you'd generate 0.44 grams CO2.  The upshot to this is that if you are normally using corn sugar and you want to switch to table sugar, you should use something like 87-percent table sugar (0.44/0.51).  This all assumes that the sugars are 100-percent fermented, which is a pretty good assumption, but you can see that when you move to other priming agents (DME, LME, brown sugar, molasses, etc.) you start to get more hand-wavy because now each of your grams of priming agent has more and more unknown unfermentables in them (water content, probably the biggest).

One reference for more geeky background on this is http://www.byo.com/stories/techniques/article/indices/21-carbonation/1276-priming-with-sugar, or even better, http://www.homebrewersassociation.org/attachments/0000/2497/Math_in_Mash_SummerZym95.pdf

[dmtaylor]

80% by volume, for sure.  Not sure about weight.  And the 80% is just a swag.  Maybe it really is more like 87%.  It's somewhere in there.

[hubie]

80% by volume, for sure.  Not sure about weight.  And the 80% is just a swag.  Maybe it really is more like 87%.  It's somewhere in there.

The 87-percent calculation is certainly only applicable for weight.  I could convince myself it would be less by volume since corn sugar can be fluffy.  That being said, my guess would be that unless you're shooting for really high or low carbonation levels, short of doing a side-by-side one wouldn't notice a 10-percent difference in carbonation levels anyway.

[Jimmy K]

This all assumes that the sugars are 100-percent fermented, which is a pretty good assumption, but you can see that when you move to other priming agents (DME, LME, brown sugar, molasses, etc.) you start to get more hand-wavy because now each of your grams of priming agent has more and more unknown unfermentables in them (water content, probably the biggest).

For using liquids to prime (I've used apple juice concentrate and maple syrup) I've had luck using the nutrition chart to get grams of sugar / serving and multiplying to get the amount needed for priming (eg. if 1tbsp has 20 grams sugar and I want 5oz of priming sugar (140 grams) then I use 7 tablespoons to prime)
 
Interesting about the different CO2 volumes from different sugars. I had no idea. I'd agree the 10% might not be noticed, especially if you don't have tight control over the amount of CO2 already dissolved in the beer.